The present invention relates to a means for digital control, which means comprises a difference-forming device arranged to form an error signal constituting the difference between a reference value signal for the control object in question and an output value signal obtained from the control object, and a device integrating said error signal and arranged to emit an output signal intended for controlling a parameter of the control object.
In digital measurement the product of measurement time and resolution and accuracy, respectively, often has a constant value. This value depends on the choice and setting of the digital convertor, which converts a measured value into digital form. More particularly, high accuracy requires a long measurement time and a short measurement time gives lower accuracy. If such a convertor is used as the output value transducer, the control performance can never be better than the convertor performance.
According to the invention, a control system is obtained which has considerably higher accuracy and/or speed than that corresponding to the performance of the output value transducer itself.